1. Field of the Invention
This invention relates to deflection wedges for oil and gas wells and particularly to deflection wedges having a conical body.
2. Description of the Prior Art
Deflection wedges have been used in drilling oil wells for many years. These wedges serve as a directional guide to exit the production tubing when drilling a secondary hole (window) from a predetermined position within a well bore into the adjacent rock or formation. Traditionally, these wedges have been limited devices that tend to guide the production tubing in a narrow range. Examples of such systems are found in the Following U.S. Pat. Nos. RE40067, RE39141, and 6,206,111, as well as numerous other patents.
The current slim hole rotary (SHR) and coil tubing drilling (CTD) industry is restricted to window exits based on current completion designs. For example, many wells in the industry have 7″ casing with 4½″ completion tubing. These wells can be serviced by SHR and CTD with mechanical means of setting a device that is run through the completion tubing and set in the larger ID production casing.
New and re-completed wells with smaller completion tubing (<3½″) that maintain larger production casing (non “mono-bore” completions, <7″, 7⅝″ and 9⅝″) present a unique challenge as they are typically not designed for a mechanical means of a casing exit. Currently these type wells incorporate the use of cement “plug back” to mill ramp up to the larger ID casing, after which they time drill an exit. In some cases a pilot hole through the cement is drilled and a whip stock is set in the pilot hole for a mechanical exit in the casing.
One problem that these types of operations have is that, when using narrow wedges, the tubing can veer away from the desired line. When this happens, the production tubing often actually runs downward, parallel to the existing well casing, instead of moving off at the desired angle.